How fast should vacuum build? - PeachParts Mercedes-Benz Forum

Diesel911 · #1 07-31-2011, 11:24 PM

The year of your 240D might give a clue if you have a Diaphragm or Pitson type Vacuum Pump.
I had low vacuum once and removing and spraying out the Check Valve that screws into the Vacuum Pump solved the problem.
Others have found the internal plastic parts of the Check Valve broken.

There is also little Disc Valves inside of the Vacuum Pump that can get cruddy.
Several years ago I also removed the Front Plate of my Piston Type Vacuum Pump and cleaned the Valves. I sheared off 2 of the Screws in the process and had to use penetrating Oil, Heat and a Hand type Impact Wrench (they type you hit with a Hammer) to get the rest of the Screws off without shearing any more of them.

Remember which direction the Disc Valves Face.

tankowner · #2 08-02-2011, 01:35 AM

Quote:

Originally Posted by Diesel911

The year of your 240D might give a clue if you have a Diaphragm or Pitson type Vacuum Pump.
I had low vacuum once and removing and spraying out the Check Valve that screws into the Vacuum Pump solved the problem.
Others have found the internal plastic parts of the Check Valve broken.

There is also little Disc Valves inside of the Vacuum Pump that can get cruddy.
Several years ago I also removed the Front Plate of my Piston Type Vacuum Pump and cleaned the Valves. I sheared off 2 of the Screws in the process and had to use penetrating Oil, Heat and a Hand type Impact Wrench (they type you hit with a Hammer) to get the rest of the Screws off without shearing any more of them.

Remember which direction the Disc Valves Face.

It's the piston type - I guess I will have to investigate. The check valve is right where the main line connects to the pump, right? Thanks for the tips.